This invention relates to a solder-bearing terminal pin or lead for attachment to a substrate, either in a receptacle on the substrate or on its surface, wherein a discrete mass of solder is mechanically held by the terminal in position to be melted for connecting the terminal to the substrate with both an electrical and mechanical bond. It is illustrated as a terminal pin or a surface-mounted terminal lead.
The terminal is of a type which is capable of being continuously stamped from a thin sheet of metal at high speed, and because each terminal mechanically holds its own discrete mass of solder, the terminals may be produced individually or, preferably, attached to a common carrier strip for automated, machine insertion into the receptacle in the substrate or for application to the surface of the substrate.
Various means have been provided wherein a quantity of solder is associated with a terminal pin so that when the terminal is inserted into a receptacle in a substrate (usually a hole drilled through the substrate with a metal surface plated on its interior and on the surface of the substrate around the periphery of the hole) or is juxtaposed to a conductive surface area of the substrate, and the assembly is heated, the molten solder covers the adjacent surfaces of the terminal and substrate to form, when cool, a soldered metallurgical joint between the terminal and substrate.
In the prior art individual terminal pins were pressed into the receptacle in the substrate and soldering was accomplished by either passing the entire substrate over a solder wave machine or by applying solder to each individual terminal pin using a conventional soldering iron and wire solder.
An alternative method used in the prior art has associated the solder with each terminal pin by means of a metallurgical bond between the solder and the pin wherein the solder was positioned in a location which was away from the receptacle or conductive area in the substrate. This method suffered from poor solder bond because the molten solder was required to migrate, such as down the terminal pin, before it could reach the junction between the terminal and the receptacle which was to be soldered.